Drilling auger



May 14, 1968 J. P. WATTS 3,382,937

DRILLING AUGER Filed M8. 2, 1966 2 Sheets-Sheet 1 INVENTOR.

JAMES R WATTS ATTORNEY May 14, 1968 J, WATTS 3,382,937

DRILLING AUGER Filed May 2, 1966 2 Sheets-Sheet 2 JAMES P. WATTS BY a ATTORNEY United States Patent 3,382,937 DRILLING AUGER James P. Watts, 6930 E. Pinchot, Scottsdale, Ariz. 85251 Filed May 2, 1966, Ser. No. 546,980 1 Claim. (Cl. 175323) ABSTRACT OF THE DISCLOSURE A drilling auger having a continuous spiral screw flight divided into an upper and lower portion axially movable relative to each other; the flights are spring-biased to permit the lower flight vertical movement relative to the upper flight in keeping with the soil conditions in which the anger is being used. A

This invention relates to a drilling auger.

More particularly, the invention concerns an improved drilling auger which is especially adapted for drilling in soils and rock formations which are drilled only with great difficulty with existing augers.

In a further particular aspect, the invention relates to rotatable drilling augers having a tapering spiral screw flight, in which a portion of the central shaft is adapted to flex upwardly and downwardly in response to varying load conditions encountered at the bottom of the drilling hole.

In a further aspect, the invention relates to earth drilling angers especially adapted for drilling in soils and rock formations of varying hardness, compaction, and other variables along the line of the drill hole.

Conventional drilling augers which are commonly and typically employed in drilling soil for piers, columns, and other building construction elements generally comprise a rotatable vertical shaft provided with a downwardly tapering spiral screw flight and cutting teeth disposed at spaced points along the periphery of the screw flight. In operation, a considerable downward pressure is exerted by the drilling machine upon the central shaft while simultaneously rotating the shaft. As the shaft rotates, the cutting teeth disposed along the periphery of the screw flight bite into the earth or rock formations and the material thus loosened is forced upwardly from the point of cutting by means of the spiral screw flight.

In many drilling situations, the cutting teeth at various points from the bottom to the top of the auger encounter variations in soil density and hardness such that the bottom portion of the auger may encounter a considerably different drilling resistance than the upper portion of the auger. Heretofore, the variations in drilling resistance encountered by the various portions of the auger necessitated adjustments in drilling pressure and rotational speed which reduced the drilling efficiency by lengthening the time required to drill a given distance and by promoting undue wear of the various elements of the auger which increased the down time for machine repalrs.

In certain types of soils, for example the so-called caliche soils, drilling with a conventional anger is extremely difficult due to the tendency of the soil to be compacted under drilling pressures to form a practically impervious glazed surface. The application of greater drilling pressure in an attempt to force the cutting teeth to bit into the glazed surface generally only results in an even denser compaction of the soil which renders the drilling operation even more diflicult. Under these conditions, it is common for a drilling auger to merely spin in the drill hole without a perceptible advance in the depth of the drill hole for a long period of time.

Accordingly, it would :be highly desirable to provide a drilling auger which automatically adjusts for varying 3,382,937 Patented May 14, 1968 drilling resistance at various points in the drilling hole, thereby substantially obviating the difliculties mentioned hereabove which are encoutnered when a conventional drilling auger is employed.

It is an object of the present invention to provide an improved drilling auger in which the lower portion thereof is adapted to move vertically upwardly and downwardly with respect to the upper portion thereof during the drilling operation in response to varying drilling resistance encountered at the bottom of the drill hole;

Another object of the invention is the provision of the above-described improved drilling auger which is especially adapted for drilling in soils and rock formations of varying drilling resistance along the line of the drill hole;

A further object of the invention is the provision of an improved drilling auger which is equipped with a yielding lower portion such that the drilling pressure at the bottom of the drill hole is varied to permit initial insertion of the spiral screw flight and cutting teeth at a point in the soil or rock structure which permits such insertion Without unduly compacting the structure to the point that it becomes glazed and offers even greater drilling resistance;

Other, further, and more specific objects and advantages of the present invention will become apparent to those skilled in the art from the following detailed description of the invention taken in conjunction with the drawings in which:

FIG. 1 is an external view of a drilling auger chosen for purposes of illustration which embodies the present invention;

FIG. 2 is a partial sectional View of the upper portion A of the auger of FIG. 1;

FIG. 3 is a partial sectional view of the lower portion B of the anger of FIG. 1;

FIG. 4 is a cross-sectional view taken along section line 44 of FIG. 1;

FIG. 5 is a cross-sectional view taken along section line 55 of FIG. 1; and

FIG. 6 is a perspective sectional view of a portion of the auger of FIGS. 1-5, showing the assembly and operative relationship of the upper and lower sections thereof.

Briefly, the present invention contemplates improvements in the conventional tapered drilling auger, such as, for example, of the type described in US. Patent No. 2,780,439 to Kandle. The conventional drilling auger generally comprises a rotatable vertical shaft having a downwardly tapering spiral screw flight carried by the shaft and cutting teeth disposed at spaced points along the periphery of the spiral screw flight.

In the improved drilling anger of the present invention, the rotatable vertical shaft telescopes and includes a hollow upper shaft portion, a lower shaft portion slidably received in and extending downwardly from the upper shaft portion, and includes means for limiting the vertical upward and downward movement of the lower shaft portion relative to the upper shaft portion.

Spring means are provided which urge the lower shaft portion downwardly with respect to the upper shaft portion. The spiral screw flight is segmented and includes an upper flight portion carried by the upper shaft portion and a lower flight portion carried by the lower shaft portion.

Turning now to the drawings, in which a presently preferred embodiment of the invention chosen for purposes of illustration is depicted, FIG. 1 is an external view of the improved drilling auger which includes a telescoping rotatable shaft generally indicated by reference numeral 1, including an upper shaft portion A which is hollow and which receives the lower shaft portion B which extends downwardly therefrom. The spiral screw flight is segmented to provide an upper flight portion 2 carried by the upper shaft A and a lower flight portion 3 carried by the lower shaft B. Cutting teeth 6 are disposed at appropriate points along the periphery of the spiral flight and the auger is provided with an appropriate cutting tip 7 and an appropriate joint 8 for attaching the auger to the lower end of the drilling machine shaft (not shown).

FIG. 2 illustrates the lower end 21 of the cylindrical upper shaft portion and the spiral screw flight 22 associated therewith. As shown, the upper shaft portion 21 is provided with a square bore generally indicated by reference numeral 23. The lower shaft portion 31, as shown in FIG. 3, is square and is adapted to be received into the square bore 23 of the upper shaft portion 21. The leading edge 24 of the upper flight portion is tapered downwardly, as shown, to provide a cutting surface when the lower shaft portion 31 (reference character B of FIG. 1) is flexed upwardly from its normal position as shown in FIG. 1.

FIG. 4 further illustrates the assembly and operative relationships of the elements of FIGS. l-3. The upper shaft portion 41 receives the square lower shaft portion 42 in the square bore thereof. The leading edge 24 of the upper flight portion 22 registers vertically with the trailing edge 43 of the lower flight portion 44.

FIGS. and 6 further illustrate the assembly and operation of the improved auger of FIGS. 1-4. The square lower shaft portion 51 is received in the square bore 52 of the upper shaft portion 53 and can move vertically upwardly and downwardly with respect to the upper shaft portion 53 a distance defined by the length of a slot 54 in the upper end of the lower shaft portion 51, the length of travel being limited by the pin 55 extending through the slot 54 and received in the upper shaft portion 53. The lower shaft portion 51 is urged downwardly by a compression spring 56 contained within the upper shaft portion 53.

In operation, the lower shaft portion and associated lower flight porton of the drilling auger flex upwardly and downwardly in response to variations in drilling resistance at the bottom of the drill hole, thereby permitting the cutting teeth on the lower shaft portion to insert themselves at appropriate soft points such as under a small stone or in a softer portion of the soil during rotation of the shaft. This prevents undue compaction of the soil at the bottom of the drill hole and substantially prevents glazing and the attendant increased drilling resistance caused thereby. Then, as the lower portion of the drilling auger encounters an area of decreased drilling resistance, the lower portion of the drilling auger can move downwardly with respect to the upper portion, without requiring a corresponding advance by the upper portion which is still engaged in the area of greater drilling resistance.

Various changes in the devices chosen for purposes of illustration in the drawings will readily occur to persons skilled in the art having regard for the disclosure hereof. To the extent that such modifications and variations do not depart from the spirit of the invention, they are intended to be included within the scope thereof which is not limited to the devices specifically illustrated in the drawings but, rather, only by a just interpretation of the following claims.

Having fuly described the invention in such manner as to enable those skilled in the art to understand and practice the same, the invention claimed is:

1. In an earth drilling auger including a rotatable vertical shaft,

a downwardly tapering spiral screw flight carried by said shaft, and

cutting teeth disposed at spaced points along the periphery of said flight, the improvements comprising:

(a) a telescoping rotatable shaft including a hollow upper shaft portion a lower shaft portion slidably received in and cooperating with said upper shaft portion and extending downwardly therefrom to permit rotation therewith and also permit relative axial movement between said upper and lower shaft portions means limiting the axial movement of said lower shaft portion relative to said upper shaft portion;

(b) spring means urging said lower shaft portion downwardly; and

(c) a continuous segmented spiral screw flight includan upper flight portion carried by said upper shaft portion, and a lower flight portion extending as a continuation of said upper flight portion and carried by said lower shaft portion.

References Cited UNITED STATES PATENTS 175,987 4/1876 Howard of a1. -381 193,348 7/1877 Robinson 175-381 331,767 12/1885 Cary 175-381 X 1,237,070 8/1917 Lundstrom 175-381 1,468,326 9/1923 Rechichar 175-381 X 2,839,271 6/1958 Kandle 175-323 X 3,226,855 1/1966 Smith 175-323 X CHARLES E. OCONNELL, Primary Examiner. NILE C. BYERS, JR., Examiner. 

